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Unknown Lameron Wednesday February 06, 2013 @01:33PM
from the prepare-for-invasion dept.

astroengine writes "Extrapolating from findings by NASA's planet-hunting Kepler Space Telescope, scientists on Wednesday said roughly six percent of so-called red dwarf stars have Earth-sized planets properly positioned around their parent stars so that liquid water could exist on their surfaces. The team looked at 95 candidate planets circling red dwarf stars observed by Kepler and found that at least 60 percent have planets smaller than Neptune. Most were not the right size or temperature to be Earth-like, but three were found to be both warm and approximately Earth-sized. Statistically that would mean six percent of all red dwarf stars should have a Earth-sized planet. Since 75 percent of the closest stars are red dwarfs, the nearest Earth-like world may be just 13 light-years away."

Hell, Asians are some of the most racist people in the world; plenty of Japanese and Korean people think their nationality is the best, and everyone else is subhuman. (And once again, the Chinese compare favorably here.)

It must've been fun writing the script for that series. "40-Eridani-System" XD Pretty much sky was the limit for throwing random shit in.Anyway Vulcans are weird. I vote that first contact should be made with the other ones.. Romulans.On topic, since noticing the other night for the first time that Betelgeuse actually looks red in the sky, and reading up on it, I've decided I'm interested in red super giants. This story about dwarfs currently has no appeal for me.

The armpit is called "the house of the shoulder" in Semetic languages, so "house of Geuse" could be understood as "armpit of Geuse". Actually, the "Bet" is thought to be a misreading of "Yad" (very similar letters in Arabic) and the name was originally "Yad al Jauza" or the "hand of Jauza". I've yet to discover who Jauza is / was but I still do have some resources to check, just not the time!

If you or your lecturer are interested in any other star names, you can contact me.

Al Jauza is the old arabic name for the constellation Orion, making Betelgeuse quite correctly the "Hand of Orion". The etymology of Al Jauza itself is unclear, at least I have nothing at hand regarding that matter.

Vulcan circles a red dwarf? Wikipedia says nothing about the planet or its star, just about the Vulcans themselves. I was thinking Krypton, even though I haven't read a Superman comic since I was 7 or 8; it orbits a red star.

I'm always amused by "only n light years away" in every story about a newly-found planet. Adams was right. "Space is big. I mean really big. You think it's a long way to the chemist..." the Voyagers have been traveling for 40 years and still haven't gotten past the heliopause. Even Adams was understating the vast distances between stars, try as he might to impress how big space is. Getting to Vulcan/Krypton is indeed infinitely improbable, at least for the next few hundred years and maybe never.

To be fair, there was a time where travel to China from the UK was considered impossibly far, taking months of time assuming you didn't get killed along the way.

Then there was the giant, impassible ocean that went so far over the horizion we were pretty sure it was the edge of the world.

Humans have this funny way of looking at something, going "Oh geez, yeah forget that!" and end up passing it off as common place some years later. I suspect humans will someday explore the stars, if we dont kill ourselves o

To be fair, there was a time where travel to China from the UK was considered impossibly far, taking months of time assuming you didn't get killed along the way.

Not literally impossible, just impractical - we had the technology required to make the trip for millennia before it became commonplace, always within the lifespan of a human being, and almost certainly within the lifetime of the civilization which bankrolled such an expedition. (Even the Roman Empire had some limited contact with China, if not for

- Within 50 years (if not much sooner), we'll almost certainly have cured aging. Once humans regularly live in the many hundreds (or even thousands) of years, a 20, 30, 50, even 100 year trip won't seem as long (plus we'll have great on-board entertainment to keep us busy thanks to advanced robotic girlfriends).

- Once you approach even half the speed of light, local time slows down for you, so e.g. a 50 year trip would be 'only' 30 or 40 years (I haven't done the exact math)

Within 50 years (if not much sooner), we'll almost certainly have cured aging.

Well, there are some folks who know a lot more about medicine and biology than I do who believe that, but it's far from a certainty. Note that the average and median life spans for people have increased greatly in the last hundred years, but wake me up when someone makes it much past 115. Those outliers have been around since antiquity, there are quite a few in my family tree from centuries ago (an uncle was into genealogy).

Well, there are some folks who know a lot more about medicine and biology than I do who believe that

I know a lot about biology and medicine, thanks to wasting half of my 20s in grad school, and I don't believe we'll have cured aging in 50 years. We may have some promising leads and a few very expensive experimental treatments, but I think it's going to take centuries before we'll have widespread longevity treatments. I would love to be proved wrong though.

The question is would you want to get that old? Sure if you can actually reduce aging and live for 500 years in a body of a 20 something. But as it stands for now, once you are past the 60s it is a downward slope and the last years may not be really worth it. If you have ever seen someone in their 90s or 100s you know what I mean.

When my grandmother was 95 she told me "I don't know why anybody wants to live to be a hundred, it ain't no fun bein' old!" Of course, she'd outlived 3 of her 4 kids, two husbands, and several doctors who all told her if she didn't cut her cholesterol down she'd die. She finally did, five years later when she fell and broke her hip. Outliving those you love is bad for your health!

However, I'm 60 and in better health than a lot of people I know who are half my age. I'm starting to get a touch of CRS, though.

That is basically the result of massive advances in public health and disease prevention, and massive reduction in child mortality (which is partly the same thing, but also specific medical advances).

Exactly. That, and better pollution controls, and OSHA keeping so many young men dying on the job, and other things that have nothing to do with medicine. My grandfather probably would have made it to a hundred if Purina wasn't too cheap to put doors on the elevator.

Unless I'm mistaken the math is straightforward; at C the trip would seem instantaneous to the traveler, so half C a 50 light year trip would seem like 25.

No, at C it would take 50 years, thus the 50 light-years distance. Consequently, the time taken at (maximum) 0.5C would probably be well over a hundred years subjective - as acceleration/deceleration would put the average speed lower than the max speed.

Actually, as I understand it, the speed of light is quite well understood. Nothing with mass can travel faster than the speed of light because the energy required approaches infinity the closer you get to C. But that does not mean we cant build a "faster then light" drive, by sidestepping the actual movement. Just look at the Alcubierre drive, sure we can't muster the energy, figure out that little strange matter problem and may actually sterilize the destination, but FTL is not totally impossible. It may n

FTL implies time travel. Relativity may not strictly prohibit it, but there is the small matter of causality to deal with. And the lack of reports of hordes of strange tourists at major historical events.

FTL implies time travel. Relativity may not strictly prohibit it, but there is the small matter of causality to deal with. And the lack of reports of hordes of strange tourists at major historical events.

Well, when speaking of FTL drive, this implies getting from point A to point B faster than light traveling between them does. There are types of drives that postulate being able to do that without actually traveling at a speed faster than light which is what implies time travel. Hyperspace is one of them because you are no longer in normal space and the normal rules no longer apply even if the two spaces are mapped to each other. Worm holes would be another (although light could travel through the worm hole

Do you really think any time traveler will risk the possibility that something they do will cause them to have never existed?

You are just making fun of bad sci-fi plots. (No offense to Star Trek or Back to the Future fans:-)

The Butterfly Effect says that the most minor change in the distant past will cause huge changes in the future, so nobody can travel back and live in their own past.At best, by arriving you fork a new timeline (or a new branch of time-lines, if you follow the Many-worlds interpretation, as sensible people do.)The problem I have with this is how can you possibly find your way back to your original time-line?

Isn't it true that any effective FTL journey from one point of view (e.g. earth), will be travelling back in time in another reference frame?And there is then nothing to stop a second such journey getting you back to earth before you left? Doesn't matter if it is wormholes or hyperspace, unless all wormholes exist in the same reference frame, ie entry and exit points at the same time in the same reference frame. And physics says there is no absolute reference frame, CBR notwithstanding.

On top of that, physics has nothing against time travel or breaking causality.

Well, I'm in the middle of writing a sci-fi book with a bad plot...:) It has time travel, FTL travel, terraforming planets that really can't be terraformed (Venus), man-made neutron stars as weapons of mass destruction, all sorts of impossibilities. But most sci-fi is really fantasy anyway. Chapter 2 ridicules Star Trek, even though I've been a fan since 1966. It's in my/. JEs.

The Butterfly Effect says that the most minor change in the distant past will cause hu

One of the major problems encountered in time travel is not that of accidentally becoming your own father or mother....The major problem is quite simply one of grammar, and the main work to consult in this matter is Dr Dan Streetmentioner's Time Traveller's Handbook of 1001 Tense Formations.

Well, if you were to travel 500 years back you'd certainly sound as funny as Shakespeare sounds to us (Data: "I'm from France"), but if someone 400 years from the future went back to 1920 there would be plenty of sound recordings and books to study. Not that I actually believe it ever happened or will happen...

Well, if an inhabited planet were only 15 or 30 light years away... there's a chance for some form of communication... a "hey we're a technological society" beacon at least. Having any evidence of another technological civilization in our neighborhood would be incredible, and might even inspire humanity to do things like colonize the solar system.

If we did find a planet with technological creatures that close, it would be a pretty good indication that tech civilizations were pretty common.

It would be pretty hard to decipher the signal, though. You've probably seen this [slashdot.org] and this. [slashdot.org] We miight not even realize the signals were from an intelligence -- Greg Egan's Luminous has an extraterrestrial race with a completely different math than ours (I read it in 1995's The Year's Best Science Fiction, it's a very good, thought-provoking read. Wikipedia says he

One attractive feature of red dwarf stars, it would seem to me, is that they have much longer lifetimes than sun-like stars. More time for complex life to evolve!

On the other hand, being (necessarily, due to temperature issues) much closer to their star, these planets are likely to be tidally locked, which is *not* a good thing for complex life trying to evolve.

Wouldn't a tidally locked planet at the outer edge of the habitable zone for a rotating planet be a nice planet on the sunny side. Near the terminus you could have nasty weather, but unless it is so cold on the dark side that "good stuff" in the atmosphere precipitates out, shouldn't the light side be reasonable for life.

Of course, gravity and temperature is only a part of what makes a planet habitable. You might want something solid to stand upon, water and other favorite chemicals, non-toxic atmosphere, e

On a tidally-locked planet, there would typically be a ring of habitable area around the sun-facing / sun-opposed side. The width of the band would vary in exact location by which part of the habitable zone it fell into, and in width by the atmosphere. At least, that's my layman's understanding that I picked up from Larry Niven's books.

It would be awfully interesting to model the climate of a tidally locked Earth-sized planet in the habitable zone. Presumably the dark side is going to be very very cold, so what does that do for atmospheric circulation patterns?

I think that's probably the one I was thinking of. The patterns might be a bit different for something in the habitable zone, but tide locked is still going to mean windy. Venus, for example, isn't tide locked but it does rotate very slowly. Winds on Venus reach 700 km/h.

The winds might diminish as you approach the point directly under the sun (or the one directly opposite). They might be eyes of giant, perpetual hurricanes. But most of the planet would be very windy.

If you have a tidally locked planet with an atmosphere, the air will be rising on the sunwards side, blowing horizontally to the night side, where it will cool, descend, and then return to the sunwards side.

So, to repeat the other poster, "Windy". The theory doesn't apply only to gas giants. (IIRC, some early modeling of Mercury even predicted this kind of pattern on Mercury, where the only gasses would be some of the heavier inert gasses and, of course, Mercury. And Gadolinium.)

A tidally locked planet would have all of its atmosphere period precipitated out on the dark side. There would be no habitable band. The antipode opposite the sun would be open to space, cooling the surface there, essentially 100% of the time. There would be no factors driving global circulation -- the atmosphere would rapidly stratify (and get very hot indeed, stably, on the side facing the sun). Eventually, where by eventually I mean in a matter of a few days if one stopped the Earth from rotating without vaporizing it (can't be done, sure, I know) it get cold enough to first rain, then snow, the snow carbon dioxide, then the greenhouse effect disappears and the temperature really plummets, and in just a little bit more time you have a rain of oxygen and nitrogen followed (as they deplete the atmosphere by a fall of solid oxygen-nitrogen sleet). As fast as it falls out on the dark side, it is replenished from the warm side (cooling as it comes) until the warm side -- now bloody hot not unlike the lit side of the moon -- has almost no atmosphere at all. The dark side has a rather large mountain of frozen air centered fairly symmetrically on the solar antipode. There would probably be some residual partial pressure of gas, but it wouldn't be enough to keep your blood from boiling anywhere on the planet's surface.

If the atmosphere was a more exotic mix, you'd actually precipitate out the gases in layers, frozen methane in one layer, oxygen in another, hydrogen and helium on top of the whole mess at the end.

Tidal locking by itself is not a fatal problem. For example, it has been estimated that if Earth were tidally locked, the night side temperature would be fairly frosty bottoming out at -33 C but that's nowhere near cold enough to cause the atmosphere to freeze out. An atmosphere anywhere above 10% of Earth's is sufficient to transfer heat to the night side. Water ice accumulation would not be a problem either, since the oceans would be free to flow underneath an ice sheet.

That was the old theory. Currently, IIUC, it is only believed to apply if there is no atmosphere. If there is an atmosphere, its circulation redistributes the heat...though slowly enough that there is, indeed, a huge difference in temperatures between the day side and the night side. Naturally, exact details depend on the composition of the atmosphere. (If Venus were tidally locked, it wouldn't change much of anything.)

On the other hand, being (necessarily, due to temperature issues) much closer to their star, these planets are likely to be tidally locked, which is *not* a good thing for complex life trying to evolve.

Do we know of any tidally locked planets?If not, why raise this supposition?

Yup. Its rarer than most people tend to think.Even though Mercury is close to being locked (and maybe becoming more so) its not locked, nor is Venus.

In fact, I've seen it postulated that only satellites with a common origin (our moon for example) are likelyto be locked, as are moons (any body, really) which has a diameter of significant size relative to the body it orbits.

Turns out there is an extra solar planet that is 'proven' to be tidally locked, but given that we can't confirm some bodies in our own solar system are tidally locked (moons of Jupiter and Saturn) I'm guessing that's based on the physics, since direct observation of extra-solar planets is pretty difficult.

On the other hand, being (necessarily, due to temperature issues) much closer to their star, these planets are likely to be tidally locked, which is *not* a good thing for complex life trying to evolve.

Another concern is that a lot of M-class stars (Proxima Centauri, for example) are flare stars. Flares are kind of a big deal when we experience them, and that's with flares that are much less powerful in proportion to the star at a distance much further away from a red dwarf's habitable zone. Imagine living 20 million or so miles from a star that arbitrarily doubles or triples its luminosity... would make for some interesting evolutionary challenges.

On the other hand, being (necessarily, due to temperature issues) much closer to their star, these planets are likely to be tidally locked, which is *not* a good thing for complex life trying to evolve.

Larger gas planets in the habital zone could have Titan/Mars size moons that may be tidally locked to their parent planet, but have an apparent "day" with respect to the parent star on the order of 48 to 200 hours long. Given that we believe there are many more moons than planets in any given system, it seems that moons would likely to be where the interesting biological action may be occurring.

On the other hand, such stars have deeper convection zones which makes their magnetic dynamos much stronger than in the Sun. The resulting magnetic activity may manifest itself in very strong flares. If the magnetic field of the planet is not strong enough, such phenomena could adversely affect the evolution of complex life forms.

The resulting magnetic activity may manifest itself in very strong flares.

Wouldn't those flares also make for large variations in radiative output? Imagine what would happen to us if Sun suddenly decided to increase (or decrease) its output by 50 percent for a few weeks or months.

Wouldn't those flares also make for large variations in radiative output? Imagine what would happen to us if Sun suddenly decided to increase (or decrease) its output by 50 percent for a few weeks or months.

Metal, i.e. any element heavier than helium is astronomical jargon, accumulates through a succession of supernovae. Theoretically some heavy early stars could if gone supernova in a billion years. Then recycled into red dwarfs as old as 11 billion years.

The summary is a bit difficult to interpret. For example, it seems like they're reporting percentages only considering red dwarf stars with planets, and then extrapolating to red dwarf stars (undetermined with/without planets). Perhaps this explains how they got a 6% estimate when 3/95 is much closer to 3%. With a 3/95 proportion of "earth-like planets" to "no earth-like planets" the 95% confidence interval for the probability of having an "earth-like" planet around a red dwarf (with planets?) is 0.66% to 8

So let's say you travel those 14 light-years, and get there to find that some holographic guy named Arnold J Rimmer has been exiled there for being a complete smeghead. I mean, that's worse than merely a wasted trip!

It's pretty cold outside here, too (at least in the north right now) and we're alone as far as we can ascertain. But why would the newly found planet not have an atmosphere? It isn't like they can tell if it has a magnetic field. If it does, and it's Earth's mass more or less, it should have an atmosphere.

Anti-space nutters always seem to judge anything space-related on whether or no we can "go there." A planet 13 light years away is a lot easier to image with practical telescopes than one 13 000 light years away.

Look, I get that you're obsessed with interstellar travel, but it ain't going to happen in your lifetime.

I can see us getting 1/2 c hundreds of years in the future.Taking 26 years to get there 26 years for some of them to get back. 10 years of study.However at 1/2 c speed. I would expect it would be better to send a probe at that speed and then send its data back at the speed of light. And really determine if there is anything worth people visiting.

However I don't see a Star Trek type of future. Perhaps most likely a Red Dwarf (TV show) future where there are no aliens that we know of and anything we do find

he was virtual, a hologram so he really didn't exist. Not until hard light at least and by then the show was more about the characters playing off against one another. That was the "Legion" episode AFAIR and introduced mamosian anti-matter chopsticks.

It's not a stupid question, my impression is that (basically) we don't know for sure. The 'consensus' seems to be that any kind of 'earth-like' or intelligent life is improbable or impossible, but that other forms of (probably simple, if they do exist) life might exist. The conditions for humans would likely be inhospitable though. Jupiter's core/surface, for example, contains a massive, deep 'ocean' of liquid metallic hydrogen.

I think more interesting though, is if Jupiter is anything to go by, big planets

Life possible on extrasolar moons [sciencedaily.com] "In their search for habitable worlds, astronomers have started to consider exomoons, or those likely orbiting planets outside the solar system. In a new study, a pair of researchers has found that exomoons are just as likely to support life as exoplanets."

Just keep in mind this field is an interesting area of active research. So take things with a grain of salt. But we have huge amounts of interesting new data coming from a.o. the Kepler observa